Long-Term Electrocardiographic Follow-Up after Repair of Tetralogy of Fallot

Background: Fallot patients with conduction disturbances are prone to sudden cardiac death. However, knowledge about long-term electrocardiographic changes after Fallot repair is limited. Methods: Measurements were performed on electrocardiograms recorded preoperatively, postoperatively, and during annual follow-up in 35 Fallot patients included in three groups: G1 if they received no patch (n = 7), G2 if they received a transannular patch (n = 13), and G3 if they received a pulmonary homograft (n = 15). Results: PR interval increased over the study period in all groups (Z-score: from 0.9 +/- 1.1 to 1.3 +/- 0.9 in G1, 0.9 +/- 1.2 to 1.7 +/- 1.6 in G2, and 0.7 +/- 0.7 to 1.4 +/- 1.3 in G3). The QRS duration increased during the follow-up at a rate of 1.78 msec/year in G1, 2.34 msec/year in G2 despite pulmonary valve replacement in 10 patients, and 1.81 msec/year in G3 despite conduit replacement in 9. At the later follow-up, the QRS duration was significantly increased (Z = 4.5 +/- 3.6 in G1, 5.7 +/- 1.4 in G2, and 4.6 +/- 1.9 in G3). One patient in each group had QRS duration of 170 msec or longer and the one in G3 had a history of serious ventricular arrhythmia. Three patients had a QTc duration above 460 msec. Conclusions: Progressive conduction disorders are noted during long-term follow-up in Fallot patients who received transannular patch but also in those who received no patch or a pulmonary homograft. It suggests that volume overloading related to the transannular patch but also pressure overloading and myocardial injury related to surgery contribute to their development. Ann Noninvasive Electrocardiol 2011; 16(4): 336-343